Cleansing the skin is a personal hygiene problem not always easily solved. Of course, the common procedure of washing the skin with soap and water works well, but at times may be either unavailable or inconvenient to use. While soap and water could be used to clean the perianal region after defecation for example, such a procedure would be extremely burdensome. Dry tissue products are therefore the most commonly used post-defecation anal cleansing product. These dry tissue products are usually referred to as "toilet tissue" or "toilet paper."
The perianal skin is marked by the presence of fine folds and wrinkles (sulci) and by hair follicles, both of which make the perianal region one of the more difficult anatomical areas to cleanse. During defecation, fecal matter is excreted through the anus and tends to accumulate in hard to reach locations such as around the base of hairs and in the sulci of the skin's surface. As the fecal matter dehydrates upon exposure to the air, or upon contact with an absorbent cleansing implement such as tissue paper, it adheres more tenaciously to the skin and hair, thus making subsequent removal of the remaining dehydrated soil even more difficult.
Failure to remove fecal matter from the anal area can have a deleterious effect on personal hygiene. The fecal matter remaining on the skin after post-defecation cleansing has a high bacterial and viral content, is malodorous and is generally dehydrated. These characteristics increase the likelihood of perianal disorders and cause personal discomfort (e.g., itching, irritation, chafing, etc.). Further, the residual fecal matter stains undergarments and causes unpleasant odors to emanate from the anal region. Thus, the consequences of inadequate perianal cleansing are clearly unattractive.
For those individuals suffering from anal disorders such as pruritis ani, hemorrhoids, fissures, cryptitis, or the like, the importance of adequate perianal cleansing takes on heightened significance. Perianal disorders are usually characterized by openings in the skin through which the bacteria and viruses in the residual fecal matter can readily enter. Those people afflicted with anal disorders must, therefore, achieve a high degree of perianal cleansing after defecation or risk the likely result that their disorders will be aggravated by the bacteria and viruses remaining on the skin.
At the same time anal disorder sufferers face more severe consequences from insufficient post defecation cleaning, they have greater difficulty in achieving a satisfactory level of soil removal. Anal disorders generally render the perianal region extremely sensitive and attempts to remove fecal matter from this region by wiping with even normal wiping pressure causes pain and can further irritate the skin. Attempts to improve soil removal by increasing the wiping pressure can result in intense pain. Conversely, attempts to minimize discomfort by reducing the wiping pressure result in an increased amount of residual fecal matter left on the skin.
Conventional toilet tissue products used for anal cleaning are essentially dry, high density tissue papers that rely exclusively on mechanical processes to remove fecal matter from the perianal skin. These conventional products are rubbed against the perianal skin, typically with a pressure of about 1 psi (7 kilopascals) and basically scrape or abrade the fecal matter from the skin. After the first few wipes, the upper portion of the soil layer is removed because the wiping process is able to overcome the soil-soil cohesive forces that exist within the fecal matter. A cleavage is thereby created in the soil layer itself with the upper portion of the fecal layer being removed and the lower portion of the soil remaining adhered to the perianal skin.
Conventional tissue products are absorbent and with each successive wipe the fecal matter becomes increasingly dehydrated, causing it to adhere more tenaciously to the perianal skin and hair and making its removal difficult in the extreme. Pressing the tissue forcefully against the perianal skin will remove more of the fecal matter but is intensely painful for people suffering from anal disorders and can excoriate even normal perianal skin, potentially causing irritation, inflammation, pain, bleeding, and infection.
Irritation and inflammation potentially caused by the use of tissue products is not limited to toilet tissue. Facial tissue products used to wipe and remove nasal discharges associated with colds, flu and allergies can also cause such problems. In addition to difficulties in breathing, seeing, and talking, an individual afflicted with these disorders frequently has a sore and irritated nose. The nose, as well as the surrounding tissue, e.g., upper lip area, are often red and inflamed to the extent of becoming painful in extreme cases.
This irritation, inflammation and redness can have several causes. A prime one is, of course, the sheer necessity of frequently blowing one's nose into the tissue, and wiping the resultant nasal discharge from the nose and surrounding area. The degree of irritation and inflammation caused by such blowing and wiping is directly proportional to: (1) the surface roughness of are in contact with the tissue. A tissue that is relatively weak or relatively nonabsorbent requires a greater number of contacts with the face than a stronger or more absorbent tissue that is able to contain a greater quantity of nasal discharge.
There have been numerous previous attempts to reduce the abrasive effect of toilet and facial tissues and to increase their softness impression. One common approach is by mechanical processing. By using particular processing steps during papermaking, toilet and facial tissue products can be made that are softer and less irritating. Examples of tissue products that are mechanically processed to be softer are shown in U.S. Pat. No 4,300,981 (Carstens), issued Nov. 17, 1981, as well as the various patents discussed in its specification.
Besides mechanical processing, others have applied emollients, salves, cleansing agents, and the like to tissue products to enhance not only the cleaning of the skin but also to reduce irritation and inflammation. This reduction in irritation and inflammation is typically achieved through either the lubricity of the substance applied to the tissue or through the therapeutic action of the substance itself. This approach is illustrated in U.S. Pat. No. 4,112,167 (Dake et al) issued Sep. 5, 1978, particularly in regard to toilet tissues. See also in U.S. Pat. No. 3,896,807 (Buchalter), issued Jul. 29, 1975 and in U.S. Pat. No. 3,814,096 (Weiss et al), issued Jun. 4, 1974 for other examples of this approach.
One substance that has been applied as a lotion to tissue products to impart a soothing, lubricious feel is mineral oil. Mineral oil (also known as liquid petrolatum) is a mixture of various liquid hydrocarbons obtained by distilling the high-boiling (i.e., 300.degree.-390.degree. C.) fractions in petroleum. Mineral oil is liquid at ambient temperatures, e.g. 20.degree.-25.degree. C. As a result, mineral oil is relatively fluid and mobile, even when applied to tissue products
Because mineral oil is fluid and mobile at ambient temperatures, it tends not to remain localized on the surface of the tissue, but instead migrates throughout. Accordingly, relatively high levels of mineral need to be applied to the tissue to provide the desired softness and lotion-like feel benefits. These levels can be as high as about 22-25 wt. % of the tissue product. This leads not only to increased costs for these lotioned tissue products, but other detrimental effects as well.
One of these detrimental effects is a decrease in tensile strength of the tissue product. As mineral oil migrates to the interior of the tissue, it tends to act as a debonding agent, thus decreasing the tensile strength of the product. This debonding effect becomes more pronounced as the level of mineral oil applied is increased. Increasing the level of mineral oil applied can also adversely affect the caliper of the tissue product.
Even without increasing its level, the tendency of mineral oil to migrate once applied has other detrimental effects. For example, the applied mineral oil can transfer to, into and through the packaging or wrapper material for the lotioned toilet tissue product. This can create the need for barrier-type packaging or wrapper films to avoid smearing or other leakage of mineral oil from the tissue product.
Accordingly, it would be desirable to provide lotioned tissue products that: (1) have a desirable soothing, lubricious feel; (2) do not require relatively high levels of mineral oil: (3) do not adversely affect the tensile strength and caliper of the product; and (4) do not require special wrapping or barrier materials for packaging.